Why strapping buttered toast to a cat's back will not produce infinite power (idea)

Ah... But the reason bread lands butter-side-down is due to the rate of rotation. If you had bigger slices of bread or higher counters, it could land right side up. It is only because the standard slice of bread rotates just fast enough that when falling from a standard counter top or table top that the bread hits top down.

So what, I hear you saying? So we use a normal slice of bread, and drop the whole thing from counter-height.

Ah!, I say again, because you've failed to take something important into account.

The cat/toast ensemble will start spinning. The cat pulls its feet under itself into landing position... But the toast yanks the cat back up! But the contraption has been falling all this time, and before you know it, the breads rotation rate is insisting that the butter side should be up.

So now you have both cat and bread pushing in the same direction! Cat lands feet first. And then, cat rolls over and rub-scratches it's back on the Persian carpet, and walks off to look for a good place to nap.